Copolymers of vinyl chloride, allyl glycidyl ether, and an allyloxyalkanoic acid



Patented Aug. 19, 1952 COPOLYMERSf-AOF VINYL CHLORIDE, ALLYL GLYCIDYL ETHER, AND AN ALLYLOXYAL- d Ellsworth K.Ellin'gboe and Henry Shirley Rothk rock,rWilmngton, Del., assignors to E. I. du Pont de Nemours & Company, Wilmington, y f Del.,acorporation of Delaware A' No Drawing. Continuation of application Serial No. .170,704,`June 27, 1950. This application June 29, 1951, Serial No. 234,455

-This invention relates to polymeric materials and, more particularly, to certain new copolymers of vinyl chloride.

`Many coating or moulding compositions fbased `on vinyl chloride -polymers and copolymers have been" described and some have achieved commercial success. However, inspite of their economic and technical advantages, the prior compositions leave much to be desiredv in respect to certain importantV properties such as initial solubility, nal nlm insolubility and non-thermoplasticity, heat resistance, andhardness. yln particular, the vinyl chloride polymer compositions heretofore known are not readily amenable to heat-curing (i. e., insolubilization upon heat treatment) and they lack 9 Claims. (Cl. ZBO-45.2)

the allyloxyalkanoic acid are between 1.2521 and 4.5:1, as the best coatings are obtained with copolymers within these ratios. However, satis- Afactory results are'oabtained within'the entire range, i. e., when the weight ratio of allylglycidyl ether to allyloxyalkanoic acid yrangesfrom 1:1 to 14:1. y. j i

Although the copolymerizationof vinyl chloride with certain other polymerizablecompounds, including allyl glycidyl ether, has'been proposed heretofore, it has'v now been -found that the comhmauon of any1 giycidyi ether with theaforethermal stability, as evidenced by the embrittlement, discoloration, and general decomposition they undergo when subjected to heat and/or light. There was al need for a thermosettinglmforming composition having the desirable propertiesof copolymers' ofrvinyl chloride, but which would also offer theadvantage of -gc'iodfiniti'al sola ubilityfcoupled `with heat curability to an insoluble,heatresistant, print-resistant, hard ilm.

' An object of the present invention is to provide a newiilm-forming, heat curable copolymer.. A further object is to provide such acopolymer which is initially soluble in common 'organic solvents but which is readily converted by heat curing to an-insoluble product characterized by excellent thermal stability and stability to light. A still further object is to provide such a copolymer which, upon heat curing, will give a heat-resistant, print-resistant, hard lm. Other objects will be apparent from the vdescription of the 'inventionv given hereinafter.

The above objects are accomplished .according to the present invention by providing a copolymer, vthe' polymeric components of which essentially consist of, by weight, 70 %85 polymerized vinylchloride, 10%-28% polymerizedallyl glycidyl 'etherpand 2%,10% ofrfa polymerized allyl etheroi a monolprimary hydroxy alkanoic acid of 'two to six carbon*v atoms, inclusive. This copolymer may sbe'prepared by subjecting toA polymerization conditions a mixture of *thel three monomeric components. i g l y In a more preferred form, the proportion, by Weight, of polyvinyl chloride in lthe copolymer is lbetween 75% and 85%, 'that ofthe allyl glycidyl ether between-10% .land':18%, and that of the al1yl-ether`of the hydroxyalkanoic acid between 4%v aand 8%;` ."Thesepreferred proportions fgive thefbestcures with mild-curingagents andoptirniirncoating properties.` Thus'the preferred ratios:` (by weight) of the allyl glycidyl ether and mentioned allyloxyalkanoic acids is unexpectedly outstanding in` its polymerization :behaviour with vinyl chloride and in its ability to impart stability tofheatvand light, aswell as heat curability and other desirable properties to the resulting copolymer, when used in the proportions stated.

A llyl glycidyl ether, which has the formula ciFon-oHz-o-CBZ-CH-'CHQ is a liquid boiling at S-88 C.,- at 80 mm.,pressure nD20 1.4345, d42f 0.9678. 'It may be prepared Iby -dehydrohalo'genation of the corresponding chlorohydrin, as" described `in U. S.' Patent 2,314,039. 1.

The third essential component of the polymerization mixtureis anV `allyl1ether of a hydroxyalkanoic kacid oftwo to six carbon atoms-in which the hydroxyl group' is primary, i. e., attachedto 'a -CI-Izgroup. Otherwise stated, it iszan a1- kanoic acid of two'to six carbon atoms having-an allyloxy groupgCHzr-CI-I-CltIz-O-f, attached to a-CH2- group. Amongjthe suitable allyloxyalkanoic acids are allyloxyacetic acid, beta-,allyloxypropionic 'acid, gamma-allyloxybutyric acid, delta-allyloxyvaleric acid, epsilon-allyloxycaproic acid, beta-allyloxyisobutyric acid, beta-allyloxyalpha, alpha-dimethyl-propionic acid, and the like. The preferred compoundsare the allyloxyalkanoic acids of the formula .Y Y

CH2=CHCn2-o-(CH2) n-COQH where n is an integer fromk 1 to 5,"inclusive- Allyloxyalkanoic acids lrin- Y particular` allyloxyacetic acid, can be prepared lby methods described in the chemical literature, forexample, in U. S. Patents 2,302,618;` 2,384,817; 2.406,59() and 2,448,246. Thechief beneficial result observed byV introduction'of the third' component,i i. e., the allyloxy-` alkanoic acid,into thel copolymer lies inthe'ffact 'that heat curabiiity immobilization) ofthe poiy-Y mers is greatly #improved therebyf One advanthan is possible' in the absence of the allyloxyalkanoic acid, thus minimizing the danger of heat discoloration in industrial practice. VIn addition, Y

these copolymers havethe advantage of superior versatility in that they can be heat-cured with. mild, non-acidic agents suchas urea-formalde#41 hyde resins, which do not give Ycomplete cure with i 1 vinyl chloride/allyl glycidyl ether copolymers'. This results in a further improvement in heat stability, since urea-formaldehyde resins `or similar resins tend to'improyel the-'inherent thermal stability of the copolymers foi' this invention.-

The invention is illustrated in greaterdetail" arefy ;v

in the following examples in which parts weight unless othenwise noted.4 Y

A stainless steel reactor was swept with city# gen-free nitrogen and charged with 36 parts of .allyloxyaetic acid. ,M4-rafts of. allyl glycidyl ether; 262vparts of thiophene-tree benzene and 6 Vparte of alphaalphaf -azodiisobutyronitri1eil??? eetlOr-Wasihl @targeted 'toga pressure 0f 90-100 mm.,"c 1osed,ool;edina solid carbon di- OXdQ/-Cetone bath and charged with 422 parts oi vinylxchloride introduced by distillation. The reactor was heated at 57-j-C.-63 C. (average 60 C.) and maintained at that temperature forlS hours with agitation, themaximum internal prese surek being 60 lb./S o. ing; Afterrv cooling to room temperatureandreleasing the residual pressure,

the benzene'solution ofthe reaction product was poured intova 4fto Gfold volumeof methanol, y Wherellpetherclymrcoasulated, Thepolymer was separated, air-dried, andredissolved in acetone.` Theacetone solution was poured into methanol andthe `reprecipitated .polymer was filtered andgdried under reducedpressure. There was obtained 148 parts of vinyl ,chloride/allyl glycidyl ether/allylxyacetic 'acid copolymer containing 76.9% "vinyl chloride as calculated from its chlorinecontent of,43.6%

This copolymer showedV superiorl heat and light stabilityv en comparison with ajcommercia'l'vinyl chloride/vinyla'cetate copolymer when tested in the form of coatings of 1 2 ml. thickness Aon phosphate-treated steel.A .Qn bakingthe vinyl chloride/allyl glycidyl ether/ allyloXyacetic-'acid copolymer coatings for dminutes'ata temperature of 177 C there was noevidence of disintegration, whereas thevnyl chloride/vinyl acetate copolymer coatingvbegan to, blacken when heated 30 minutes at149 C. an'd'was quiteblack and disintegratedin dminutesgat 177 C. v

. Thecopolymer of this example was initially soluble in solvents. such as acetone, cyclohexi anone or a 1:1 mixture of Xylene and methyl isobutyl ketone.. Uponbaking coatings of this copolymer at 149 C. for 30 minutes, there were obf tained tough ilmsinsoluble in the above-men'- tioned solvents. By addition to the copolymer of 2% of butanol-modified urea-formaldehyde resin followed by baking -30 minutes atv 121 C., there Were obtained well-cured coatings having outstandingorganic'solvent in solubility as well as excellent hardness and heat-resistance.

A glass'reactorlwas charged with' 1*'.4part`s of sodiumv hydrazobis-methanesulfonata ,0.1.41part of cupric chloride,80 partsofwater, 125 p'artso'igVV ethanol, `3,5 partsofallyloxyaceticacid, and 12.2.-

parts of vallyl glycidyl ether, then cooled to 70 ride. The reactor was purged with nitrogen,

sealed, allowed to warm to room temperature y( C11-2 C.) land maintained'atthat temperature-"for V2 hours. After cooling and releasing the residual pressure, the reactor was discharged. The polymer was ltered oi, thorough- Vly Washed with water to remove Water-soluble solid's,` washedwith methanol and dried under reduced pressure.; There was obtained 12.4 parts of-a whitecopolymer of vinyl chloride, allyl glycidylether, andallyloxyacetic acid which conytained 133.6% by Weight of vinyl chloride, as indicated ]oy its chlorine content of 47.5%, and 5.1% oallyloxyacetic acid, asindicated by Van acid number of 24.7.- AA solution of this copolymer in jcycloheiianon'e had a viscosity of 3.0 poises xylene and methyl isobutyl ketone.,V Coatings applied' at l 2 mil thickness overp -hosphatized steel and baked 530 minutes at 1.21 had excellent properties, including gloss, color, .-flexibility, A resistance Yto printing at QSfCQandresistance to attack by organic solvents orhot soap solutions. Addition'to the enamel ci 2%, based on total solids, of a soluble lead salt, such as basic lead octoate, gave a composition which ,cured Well at 121"l C. and was unchangedin propertiesrwhen bakedat temperaturesfas as150b C. Y

Example -III' I A copolymer was prepared asdescribed in EX- ample I,using 18 par-tsof allyloxyacetic acid, 162 .parts 01..Y a11511. .glyQdylthen 420 oar-tsY Vof vinyl Chloride; @parts Qf elohaalrhaf -azodsobutyfoeitrle, @M1-262 parte "of: benzene.- This mixture wasileated at @1218. hours. the maximum v inter-nalpressurebeingj@ lbs/sq. v' lhe-re was obtained 191 parts of avinyllchloride/ allyl glycidyl ether/allyloxyacetic acid, copolymer containing 81.5% of polymerized vinylchloride and in 30 minutes at '121 C. to givellms having-excellent flexibility, toughness, impact resistance and solventresistance.

. A "A copolymer was lpif@Dird by theprocedure of Example 4I' Vlisibles `12,158. :partsfot vinyl; chloride. 7o

tartsY ,of allyl elycidykether, f2.0. :parts Vof allyloxypropionicacid, 13 parts of v-a pha,'alpha' azodisof ity, heat stability s'tainlesssteelY reaction vessel. There was Vopbtained '72 parts of,4 al vinyl chloride/allyl glycidyl ether/allyloxypropionic acid copolymer containing 81% of polymerized vinyl-chloride (46% chlorine) and I12.37% of polymerized allyl glycidyl ether. vThis polymer had a viscosityrof 1.83,poises in 30% cyclohexanone solution at 25 C. ,It was similar to the copolymer of Example I in solubiland 'curingV properties in baked coatings. r' Y The allyloxypropionic acidV used in `this example was prepared -,by condensing beta-propiolactone with allyl alcohol, Il', had a boiling point of 92 C. at, 0.5 mm. pressure, a refractive index NDF of 1.4399 and an acid number of 437 (calculated 431`).`

Example VI A copolymer was4 prepared as in Example I by heating at 605 C. for 18 hours a mixture of 202 parts of vinyl chloride, 7 5'parts of allyl glycidyl ether, 25 parts' of allyloxypropionic acid, 3

parts of alpha,alpha-azodiisobutyronitrile and 131 parts of benzene. There Was obtained '71 parts of copolymer containingl 78.2% of polymerized vinyl chloride and having a viscosityof 1.33 poises in 30% vcyclohexanone"solution at'25 C.This'polymer cured readily in the presence of 2% of a butanol-modiedurea formaldehyde resin at 149 C. andshowed superior heatv stability.

It will be understood'that: the above examples are merely illustrative `and that the `present invention broadly comprises a copolymer, the polymeric components of which essentially consist of, by Weight, 70%-85% polymerized vinyl chloride, 10%-28% polymerized allyl glycidyl ether, and 2%-10% of a polymerized allyl ether of a mono- (primary hydroxy) alkanoic acid of 2 to 6 carbon atoms, inclusive. a

The vinyl v chloride/allyl glycidyl ether/allyloxyalkanoic acid-copolymers of thisl invention may also contain'minor amounts, up to about 25% by weight of the total polymeric material, of other copolymerized ingredients. These` may be the polymerization products of any unsaturated compound copolymeri'zable with vinyl chloride, preferably a monoethylenic compound having a terminal methylene group attached by a double. bond tothe restofthe molecule. 'Examples `of such'compound's are ethylene,- isobutylene, vinyl trirnethylacetate, methyl methacrylate, acrylonitrile, dimethyl fumarate, allyloxyethanol, glycerylfalpha-monoallyl ether, allyl 'ethers of glycerol monochlorohydrin, di(betahydroxyethyl) maleate, vinylidene chloride, tetrafluoroethylene, etc. y

The copolymers of this invention may also have combined with them various extraneous nonpolymerizable adjuyants such as dyes, pigments, reinforcing agents, fillers, plasticizers, stabilizers, oils, etc. Polymeric modifiers such asnondrying oil-modified alkyd resins, or fvarious vinyl chloride copolymers, are especially useful.

The copolymers. of this invention are prepared by polymerizing togethervand in suitablev proportions vinyl chloride, allyl. glycidyl etheig. and an allyloxyalkanoic acid as above defined, alone/or, optionally, with onerorf more additional polymeriz'able componentsfin minor amount.' The proportions of polymerized allyl glycidyl ether and allyloxyalkanoic acid in theresulting poly-y mer 'arefairly close to their relative proportions inthe monomeric mixture but the vinyl chloride has a tendency` to polymerize somewhat faster than the other components and, therefore,

those of the free radical-generating type such as are jthef'followinglrecently proposed combina-V to, -appear inthe polymer in somewhateieater proportion than Ain the monomericmixture.;

- The actual compositionY of the polymerdepends to some extent on theconversion and the particular conditions of polymerization and lto determine the ,composition of the resulting' copolymer Within practicalV limits necessitates determining the .proportion Aof vinyl chloride by analysis. A readily carriedout determination of 1 ,theY chlorine content will'establish the proportion vof polymerized vinyl chloride in the `copolymer which will usuallyrun fromY 5% .to 10% Vgreater than in the monomeric mixture or sometimesup to as much as 25% more, Vparticularly when the'low vtemperaturepolymerization initiators discussed hereinafter aroused-` i 1 -f .f Determining the proportion .of ,allyl elycidyl ether and allyloxyalkanoic acid. is: much. more difcult and subject to error. It has been found that as a matterof practice and forthe degree of accuracy vrequired bythis invention, the pro,- portionof these latter Vtwo components need not be determined byy analysis but simply caribe asallyl glycidyl ether, and from 3% to15%lofally loxyalkanoic acid. Further, if analysis shows` that the vinyl chloride lcomponent of the copolymer is between and.85% andwthepallyl glycidyl ether and 'allyloxyalka'n'oic acid were present inV thev original mixture inthe proportion between :1 and'4.5:l, the copolymerwill, for all prac- .tical purposes, be Within Vthe,preferred proportion rangebfthisinvention. It will be understood that it isnot contended the relative proportion` ofl allyl-'glycidyl ether and allyloxyalkanoic acid to "each'f other uremains .identically the Asame in thecopolymer as it was in the monomeric mixture' -butthat the variation .is not material. I

The .preferred polymerization -initiators are organic or inorganic peroxides, e. g., hydrogen peroxide, benzoyl. peroxide,y lauroylz,7 peroxide,

tert-butyl hydroperoxide,- Ydiethyl peroxide, andy the like; or the persalts suchfas ammonium,;po tassium, or sodium persulfates,Iperborates,Y or percarbonates, with 'for vwithout: reducingfQad-L infantsv sich assoi-'fufdicxide sodium suina, so-

I diumV hydrosulit'e, etc.; the azo compounds described in S'. Patent 2,471,959, e. g., vthe aao'nitriles such ,as alphaalphaf -azodiisobutyronit'r'ilejY alphaelphaf-azobis(alphagamma di,- methylvaleronitrile) ;dimethyl alphaalpha'^azo diisobutyrate 1,-1-azodicyclohexanecarbonitrile" and the like. The'azonitrileinitiators are preferred in theproduction ofthe copolymers of this invention since they: give-products-'hav'ing the bestrthermalY stability. l Excellent initiators for use in aqueous vsystems tionszf. a water-soluble metal'thiocyanate withhydrogen peroxide or an organic hydroperoxide arid-% and the allyl elytones.

- '7 (as. disclosed-application vSerial No. 138,525, iiled by E.,G.-'IIovvard on January 13, 1950); a salt of a Vhydrazobisalkanesulfonic acid, such as sodium hydrazobismethanesulfonate, with hy drogen peroxide andi-a cupric or ferrie ion (as disclosed.` inapplcation Serial No. 141,867,11ed by- E.`Gr.V HOWardonFebruary l, 1950fand now Patent No. 2,589,258). These systems are efiective atremarkably lovv temperatures, e. g., be-` tweenl `"25?, C. fand +40". C.- The catalyst need be used oni-yin inixioramounts, e. g., between 0.01% and 5% based on the Weight ofthe total polymerizable materials. f

Y The polymerization can be carried out under a'variety of conditions While a solvent is not essential, it is convenient in practice to use a liquid medium Whichdissolv'es' the monomers and catalyst.- 'Any' Vinert rsolvent maybeused, in^` cluding' those `which "are also solvents kfor the polymer, e. g;, laronfiatic hydrocarbons such as benzene, toluene;v and the xylenes or ketones such as acetone, methyl isobutyl ketone, cyclohexanone, etc., andthose which do not dissolve the polymer, such as Vmethanol, ethanol, butanol, tert-butyl alcohol,` aceticacid, aliphatic hydrocarbons, etc.' ,Alternativelmthe polymerization ,mayY be carriedoutin^aqueous systems, with or WithoutA dispersin'gemulsifying agents. y

rThe Vvp 'olyme'riz/.ation :may include ingredientssuch'as tert-butylortertiamyl al cohols Whicli'generailyf''actv as buffers --in vinyl chloride polymerization to neutralize the' hydroof such agents, it is possible to insoiubiiize ine resins 'at' lov/er temperatures for example, by

heating at 100 to 175 C. for 10 to 30 minutes; or,

alternatively, at higher temperatures, such as 14o-250 C., butin less time than is possibleat the' same temperature without a curing agent. VAfter complete curing, the 'resins are substantially insoluble in and unaffected by the common solvents, including th-Ose, such as aromatic hydrocarbons or ketones, which dissolved them before the heat treatment. f The copolymers of thisv invention'are particulariy 'useful in the coating and impregnatng ci porous surfaces suoli` as textiles, e.- g., cotton fabi rios or regenerated cellulose fabrics; paper, wood, brick, etc., and in the coating of nonporous surfaces such as iron, steeLglass, and the like. They are also useful in such applications as wire coating and can coating, and the preparation of molded andV extruded articles, adhesives, unsupported A nlmsf, ii'bers, and the like.

gen chloride which' may beformed, or maleic anhydride" 'Whicl-i often 'oonferslbetter adhesive properties; vH'ev'veveitthese adjuvantsare by no means necessaryv since allyl'glycidyl ether itself acts as abuer and-since the' allyl glycidyl ether/Vinyl chloride/allyloxyalkanoic acid copolymers themselves ha-'ve' excellentV adhesive properties. I Y

The *polyme'riza'tion`MV temperature is notcritical. At low temperaturesfe. g., 0-l0 C., the reaction is rather slow except when the low temperature initiatorsl mentioned labove are employed, in Which case the'reactio'n maybe carried out even at temperature's as lowes-E25", C. Itis usually expedient tooperate attemperaturesfabove 25 C.

and preferablylbetweene" Cl and 1005 C. InY view kofthe Volatility of viry1` chloride, it isdesirable to useisealedreac'tors; The` reaction may be'carried out under the autogenous pressure of the reactants at the reaction temperature but,'

advantage of ready` solubilityy in many common solvents, particularly' the aromatic mononuclear hydrocarbbnsand 'thefaliphaticor alicyclic ke The polymer maybe" cured,I tha't'is'ren deredv insoluble intlie'same solvents, by means'of av heat treatment-'at temperatures 'between' about 120 "C.' and 250 'G foi' l peiodsfvarying', depeh`dingon thetemp'erature,between 10 and 45 minutes. However, Vthe" heat-curing. or thermosetting of. thefcopolynier is' preferably carried outV with the aid yof. smallV amounts, from 0.1 to" 5% by' weight, ci Ycuring orthermosetting agents.

Preferably, the curing agents are.` organic solvent-soluble; .ureafformaldehydd or melamine-formaldehyderesins, vwhich may beusedzas such or inconv` Neotion; with ,an-as ic-safielystf -with the: help This application isa continuation oi applicantscopending application Serial No. 170,704, filed June 27, 1950, and entitled Polymeric Ma'- terials, now abandoned; M

As many apparently Widely different embodi ments of this invention may be made Without departing from the spiritV and scope thereof, it is to be understood thatl the invention is not limited to the specific Vembodiments thereof except aside# fined inthe appended claims.

rIhe invention claimedis: Y j Y l. A copolymenthe polymeric lcomponents of which essentiallyconsist or, by Weight, 70%85'% polymerized Vinyl chloride, 10 %-28 polymerized allyl glycidyl ether, and 2%-1'0% of a polymer-V ized allyl ether ora monofprimary hydroxy) aliranoic acid Yof Vtti/'o to sixv carbonatoms, inclusive.

2. A copolymer as recited in clai'mvl wherein said allyl ether is an allyloxyalkanoic acid of where n is an integer 'oflfrorn' l'to l5, inclusive. 3. A copolymer as' recited' in claim 1 wherein said allyl ether is Vallyloxyacetic acid. n

4. A copolymer, the' polymeric components of n acid'of twoV to siX carbon atoms, inclusive.' p

A copolymer as recited in Vclaim 4 wherein said allyl etherY is an allyloxyalka'rroic acid of the formula CHzCH-CHz'fOL'CHzL-COOH where n is an integer' of. from 1 to' 5, inclusive;M

6. A copolymer as recited in claim vvi wherein said allyl ether is allyloxyacetic acid.'

7. A cured copolymer as set forth inclaiin l, said copolymer having been cured in the presence of an `organic solvent-soluble resin from Vthe group consisting of urea-formaldehyde and melamine# formaldehyde. Y f

8. Process' of curing" whichV comprises heating the copolymer set' forth in claim lat a temperaiure cf 120 C. 1:o"25,0 'C Lin" tneprsence f an organic solvent-soluble resin frointhe group consisting of ureaeiorrnaldhyde land melamineformaldehyde.

kmodified urea-formaldehyde resin.

9.y Process set forth'y:` in' claim 8' wherein said curing is carried'out in me presence of' abuiani ELLsWoRTH K. ELLINGBOE. HENRY vSHIRLEY R'o-THRoCK.

lio'referencesciige'd.Y t 

1. A COPOLYMER, THE POLYMERIC COMPONENTS OF WHICH ESSENTIALLY CONSIST OF, BY WEIGHT, 70%-85% POLYMERIZED VINYL CHLORIDE, 10%-28% POLYMERIZED ALLYL GLYCIDYL ETHER, AND 2%-10% OF A POLYMERIZED ALLYL ETHER OF A MONO (PRIMARY HYDROXY) ALKANOIC ACID OF TWO TO SIX CARBON ATOMS, INCLUSIVE. 